This invention relates to wear-resistant aluminum alloy for automobile parts, particularly, to an aluminum alloy for automobile engine and transmission parts having high strength and toughness, and excellent wear-resistance which is prepared by increasing the amount of silicon, copper, magnesium and titanium, and decreasing the amount of zinc.
A typical, die casting aluminum alloy having wear-resistance consists essentially of 16.0 to 18.0 wt. % of silicon, 4.0 to 5.0 wt. % of copper, 0.45 to 0.65 wt. % of magnesium, less than 1.3 wt. % of zinc, less than 1.3 wt. % of iron, less than 0.5 wt. % of manganese, less than 0.1 wt. % of nickel and less than 0.2 wt. % of titanium, which shows excellent tensile strength and wear-resistance, but elongation is low due to sludge factor of impurities such as tin etc. Accordingly, when it is used for automobile parts, particularly a manual transmission(MTM) shift fork, it may be broken.
Japanese patent non-examination pyoung 2-61023 discloses another aluminum alloy which shows good thermal resistance and wear-resistance, wherein the aluminum alloy comprises 5 to 35 wt. % of silicon, 1 to 15 wt. % of iron, 0.3 to 10 wt. % of manganese, and 0.1 to 5 wt. % of cerium, tungsten, titanium or molybdenum and the average diameter of the silicon is 20 .mu.m.
The aluminum alloy of the above composition has good thermal resistance and wear-resistance, but it has severe brittleness at the elevated temperature and a low toughness at room temperature.
This invention solves these problems associated with the conventional aluminum alloys. The preferred aluminum alloy of this invention shows excellent strength, toughness and wear-resistance, and is prepared by increasing the amount of silicon etc., decreasing the amounts of zinc and newly adding titanium and berylium.